9DKF

Ca2+ bound aplysia Slo1 R202Q

9DKF の概要

• エントリーDOI: 10.2210/pdb9dkf/pdb
• EMDBエントリー: 46956
• 分子名称: BK channel, POTASSIUM ION, MAGNESIUM ION, ... (4 entities in total)
• 機能のキーワード: potassium channel, calcium-activated, voltage sensor, large conductance, membrane protein
• 由来する生物種: Aplysia californica (California sea hare)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 479350.52

構造登録者

Gustavo, G.F.,Shen, R.,Latorre, R.,Perozo, E. (登録日: 2024-09-08, 公開日: 2025-06-18, 最終更新日: 2025-07-16)

主引用文献

Contreras, G.F.,Shen, R.,Latorre, R.,Perozo, E.
Structural basis of voltage-dependent gating in BK channels.
Nat Commun, 16:5846-5846, 2025

PubMed Abstract: The allosteric communication between the pore domain, voltage sensors, and Ca binding sites in the calcium- and voltage-activated K channel (BK) underlies its physiological role as the preeminent signal integrator in excitable systems. BK displays shallow voltage sensitivity with very fast gating charge kinetics, yet little is known about the molecular underpinnings of this distinctive behavior. Here, we explore the mechanistic basis of coupling between voltage-sensing domains (VSDs) and calcium sensors in Aplysia BK by locking the VSDs in their activated (R196Q and R199Q) and resting (R202Q) states, with or without calcium. Cryo-EM structures of these mutants reveal unique tilts at the S4 C-terminal end, together with large side-chain rotameric excursions of the gating charges. Notably, the VSD resting structure (R202Q) also revealed BK in its elusive, fully closed state, highlighting the reciprocal relation between calcium and voltage sensors. These structures provide a plausible path where voltage and Ca binding couple energetically and define the conformation of the pore domain and, thus, BK's full functional range.

PubMed: 40593533
DOI: 10.1038/s41467-025-60639-y

実験手法

ELECTRON MICROSCOPY (2.6 Å)